What I'm thinking is that a beta.en.wikipedia.org instance wouldn't be so bad, if it had the same data on the back end.
Along a similar vein, would it help to have a public test wiki that always ran the absolute bleeding edge? (As opposed to test.wikipedia.org which runs an NFS checkout before the sync, and as such usually differs little from most of the Wikipedia sites). Example hostname: http://dogfood.wikipedia.org/ . That way keen people could try new stuff out earlier, and maybe we might get some feedback sooner, before changes impact the whole userbase, thus possibly resulting in greater harmony?
All the best, Nick.